How do hydrophobic interactions help proteins fold?

Hydrophobic interactions are a critical force in the folding of proteins into their functional tertiary structure. These interactions occur between the nonpolar side chains of specific amino acids, such as valine, leucine, isoleucine, and phenylalanine.1

In an aqueous environment, these nonpolar side chains tend to cluster together to minimize their contact with water. This clustering results in the displacement of water molecules from the vicinity of these nonpolar groups. By sequestering these hydrophobic regions within the interior of the protein molecule, the polypeptide chain is driven to fold into a stable, compact conformation.12

This process is essential for maintaining the native state of globular proteins. If these interactions are disrupted—for example, by the introduction of organic solvents—the protein may undergo denaturation, leading to the loss of its biological activity.2